Non-clogging centrifugal pump



June 16, 1959 E. uMBRlcHT ,2,890,666 f NON-CLOGGING CENTRIFUGAI. PUMPFiled May 26, 1953 A3 Sheets-Sheet 1 June 16, 1959 2,890,660

E. UMBRICHT NON-CLOGGING CENTRIFUGAL PUMP Filed May 26, 1953 3Sheets-Sheet 2 I lNvENToR EM/L 0MB/WOW' E. UMBRxcHT 2,899,660

June 16, 1959 NON-CLOGGING`CENTRIFUGAL PUMP Filed May 26, 1953 3Sheets-Sheet 5 FIG. 4.

United States Patent NON-CLOGGING CENTRIFUGAL PUMP Emil Umbrcht,Jackson, Mich., assignor to Aiem Laboratories, Inc., Detroit, Mich.

Application May 26,1953, Serial No. 357,450

6 Claims. (Cl. 103-103) This invention is in the eld of centrifugalpumps for pumping liquids, and in particular relates to an improvednon-clogging pump. The invention has particular utility for pumping andcirculating large volumes of contaminated liquids and for maintaininghigh pressures over long periods of time regardless of the degree ofcontamination of the liquid pumped.

The invention is described as embodied in a pumping assembly for use inpower washing equipment and spray washing booths wherein the pump-shaftbearing assemblies are readily accessible and require little servicing.

In pumping the large quantities of liquid which are continuouslyrecirculated in power washing applications, one of the most troublesomediiculties encountered with existing pumps is that they become cloggedin a relatively short period of time. Many existing pumps have a highinitial capacity and can deliver a satisfactorily high pressure whenthey are rst placed in operation, but due to the large amount ofrecirculation and the increasing contamination of the Washing solutionthese pumps soon become clogged. Their capacity and delivery pressuredrop off until eicient operation ceases. With these existing pumps aconsiderable portion of the working time is lost because of the requiredfrequency of dismantling and cleaning.

Another diculty of existing pumps is that their bearing assemblies areimmersed in or exposed to the contaminated washing solution which oftenhas a corrosive effect on the bearing surfaces. In this way the bearingsare rapidly worn and require an early replacement. Moreover, in manysuch washing solutions there are high concentrations of detergents orother solvent agents which make it dillicult to maintain adequatebearing lubrication wherever the solution strikes the bearing surfaces.The bearing packing deteriorates from excessive friction and in manycases troublesome leaks have developed.

The described embodiment of the invention successfully operates underthe most severe working conditions. For example, in many power washinginstallations an object to be painted is rst washed under a highpressure jet of detergent laden water. The combined washing and solventaction serve to remove scale, dirt, and grease, which go into thewashing solution and are recirculated through the pump. Occasionallyeven wiping cloths fall into the washing solution. The pump describedherein operates at high eiciency in spite of the heavy quantities ofsticky and dense dispersions formed in such power washing installationsand successfully handles solids in the washing solution such as rustscales, dirt particles, pieces of cloth, and the like.

It is an object of the present invention to provide an improved,simplified non-clogging pump for handling contaminated solutions andrequiring a minimum of maintenance.

Various other objects, aspects, and advantages of the present inventionwill be in part pointed out and in part apparent from the followingdescription considered in conjunction vwith the accompanying drawings,in which:

lce

Figure 1 is a perspective view, on enlarged scale, of the impeller andcasing of a simplified heavy duty pump embodying the present invention,shown partially broken' away;

Figure 2 is a vertical axial cross-sectional view of the whole pumpunit;

Figure 3 is a vertical, fragmentary sectional view through the impellerassembly and casing;

Figure 4 is a horizontal cross-sectional view taken along the line 4-4in Figure 2, looking down on the impeller and pump scroll;

Figure 5 is an enlarged elevational view of one of the impeller blades;and

Figure 6 is a bottom View of the blade shown in Figure 5.

In operation the impeller 10, pump casing 12, and a bottom portion ofthe pump shaft 14, and of the lower shaft housing and casing support 16project below the level of the washing solution 17. The centrifugalimpeller 10 is rotated in a clockwise direction as seen in Figure 4, andthe washing solution is sucked up from the bottom into the intake port18, as shown by the arrows 20, and driven out through the discharge port22 (Figure 4) in the direction of arrow 24 at a relatively highpressure.

In order to provide a large capacity and to enable the pump to handlethe various solid matter discussed above, which is likely to occur inthe washing solution, the intake port 18 (see Figure 3) has a largediameter equal to the full diameter (see Figure 4) of the centralimpeller space, indicated at 26, inside of the inner or leading edges 28of the eight impeller blades 30. The intake port 18 is immediatelyadjacent the impeller space 26 and has a sharp projecting edge 31. Thus,this pump has a wide intake orifice and a very short intake path throughwhich the washing solution travels while being sucked into the centralimpeller space. The result is that in spite of any stickiness of thesolution, the pump is not required to overcome any significant intakepressure drop. Moreover, the relatively long sharp edge 31 co-operateswith the impeller blades 30 to chew up rapidly any lumps of dirt orpieces of cloth in the solution 17.

The eight impeller blades 30 are vertically mounted from the undersideof an impeller disk 32, which is welded to a collar 33, held onto thebottom end of the vertical pump shaft 14 by a pin 34 and nut 35. As theimpeller blades revolve, they drive the washing solution out from thecentral space 26 into an exit channel 36. This channel 36 is formed bythe space within a bottom Wall or casing plate 37, an outer casing wallor pump scroll 38 of approximately involute shape, and a top wall orcasing plate 40. To provide access to the impeller, the top casing plate40 is detachably supported atits inner edge from an impeller cover 42,welded along a seam 43 to the bottom of the lower shaft housing 16,which in turn is supported from a mounting plate 44 for the whole pumpassembly. For ease in mounting, the mounting plate 44 may be square inform and may have a number of bolt holes 46 spaced around its edge toco-operate with bolt holes formed around the inner edge of an opening inthe top of the tank for the solution 17.

To provide a relatively high exit velocity and pressure, the impellerblades 30 are tapered to decrease their size in going from their inneredges 28 to their outer edges 48. The bottom or clearance edges 450 ofthe blades 30 are inclined upwardly and outwardly and are spaced withuniform clearance from the upper inclined surface ofy a casing ring 452.This ring 52 has the form of a truncated cone, shown in section inFigures 2 and 3, and in these figures the bottom edges 50 of blades 30are Lshown as straight to emphasize that a uniform clearance exists b6-tween them and the ring 52. Actually, the clearance edges `S of theblades are curved, as shown in Figure 5. These blades are vertical and(see Figure 4) are set at an angle with respect to radii from the axisof the impeller so that their bottom edges must approximate portions ofa parabolic curve.

As seen in Figure 3, the sharp inner lower edge 31of the casing ring 52forms the edge of Vthe intake port discussed above. This edge 31projects slightly below the bottom casing plate 37 and is welded along aseam 54 to the inner edge of the bottom plate 37. The outer edge of thecasing ring 52 is supported by welding along seam 56 to a cylindricalbrace 58 welded at points to the bottom casing plate 37.

The uniform clearance along the edges 50 and the relatively large sizeof the exit channel 36 feeding into the discharge port 22 give evenfurther protection against any clogging of the pump.

Further protection against clogging is obtained by using a relativelylarge clearance between the upper or reverse surface of thesubstantially imperforate impeller member 32 and the cover 42.

Because of the high pressure existing in the outlet channel 36, there isa tendency for the liquid to flow or leak back up past the edge of theimpeller disk 32 into the large clearance between the cover 42 and thedisk 32 and inwardly toward the shaft 14 and then up between the inneredge of the cover 32 and the shaft 14 into the interior of the lowershaft housing 16. To prevent this leakage or reverse flow from buildingup within the lower shaft housing 16 and reaching the lower bearingassembly 60, which rests on top of the mounting -plate 44, fourauxiliary impeller blades 62 are attached to the upper surface of theimpeller disk 32. As seen in Figure 4, 4these four auxiliary irnpellersare the same horizontal length as the main blades 30, but are of littlevertical height, and are at the same inclination as the blades 30, beinglocated directly above alternate blades 30. These auxiliary impellerscreate an outward thrust and act to prevent any substantial reverse flowinto the housing 16. Moreover, leakage holes 64 are formed in thehousing 16 below the level of the washing solution 17 so that any slightresidual reverse ow is readily discharged from the housing 16. Anotheradvantage of the auxiliary blades 62 is that they act to chew up anysolid material which may find its way into the clearance between the topof the impeller disk 32 and the cover 42. The large clearancetherebetween allows the freeing of any such material.

Among the advantages of this pump are those which ow from the fact thatthe impeller is free from the close presence of any bearings. The intakeopening 18 is entirely free, nothing obstructs access to the impellerspace 26 so that the impeller blades 30 can rapidly chew up any solidmatter therein to free the pump. Also, the top surface of the impelleris free; any solid matter in the clearance space under the cover 42 isquickly ground up, and there is no bearing assembly nearby to become y 4a multiple V driving sheave 72 around which run several V-belts 73driven by a sheave 74 of smaller diameter connected to an electric motor76. With this belt drive the necessary reduction in speed and increasein torque is obtained; the motor 76 is substantially isolated from anyshocks from the impeller 10. However, in many installations a reductiongear transmission or a direct drive, with a special low speed electricmotor, may be used.

The lower bearing assembly 60 includes a bearing support 78 with aninner alignment socket opening upwardly, in which rests the outerbearing race 82. The ball A bearings 83 run between this outer race 80and an inner mounting plate 44, whereby the whole pump assembly bearingassembly 66 is supported upon the cover -68 restis a self-containedunit, or the motor 76 may be separately mounted, and the V-belts 73 willbe of an appropriate length to accommodate the motor installation.

Another advantage of this pump is that the length of the lower housing16 and shaft 14 may be varied to accommodate the pump to different typesof installations, wherein the casing and impeller are required to belocated at various depths below the liquid surface.

I lhave found that it is preferable to have the distance between themounting plate 44 and the liquid level no less than 2 inches in order toprevent the liquid from approaching unnecessarily close to the lowerbearing. However, Where it is required to have the mounting plate 44closer to the liquid than this, seals may be placed below the lowerbearing to exclude the liquid therefrom. In any event, the leakage holes64 are provided, preferably always located beneath the liquid level.

Following is a description of certain aspects, dimensions, and featuresof a pump assembly which has proven highly successful for continuous usein power washing installations in connection with paint spray booths.This pump is fabricated from at stock material and eliminates the needfor complicated expensive castings, all joints are welded or bolted, asshown in the drawings.

The impeller disk 32 is 1% inch thick and has a diameter of 121%2inches. The main impeller blades 30 are 1A inch thick and are 2%6 incheshigh along their inner edges 28 (Please see Figure 6.) which are roundedalong their length to a M4 inch radius for streamlining effect. Theouter edges of the blades are 1% inches high. These blades are 317/32inches in length from inner to outer edge as seen in Figure 5 and theirbottom edges have a curvature or bulge of about i732 inch in the center.These eight blades are arranged vertically and welded to the impellerdisk 32 at an angle of 70 to radii passing near their leading edges, sothat they are equally spaced 45 apart as measured around the impellerdisk. The effective impeller diameter measured across the outside edges48 of the blades is 12% inches, and the diameter of the central space 26within the edges 28 is 7 inches. The impeller collar 33 is 1% incheslong with an O.D. of 21/2 inches and an I.D. of 1.625 inches, with a 1Ainch x 1A; inch vertical keyway, and a 1A inch pin 34.

The casing ring 52 has a slope of 25 the diameter of its inner edge 31is 7 inches and this edge projects about 1,46 of an inch below thebottom 37. A vertical clearance of 1A; of an inch exists between thesloping ring 52 and the bladeedges 50, and a large clearance S of. 1%;of an inch exists between the cover 42 and the disk 32. The fourauxiliary blades are about 9/322 0f an inch high, thus with a clearanceof about 1A; of an inch from the cover 42. The height of the scroll 38is equal to` Athe spacing betweenl the bottom 37 and the top 40 and is2%v inches.

From this description it will be understood that the present inventionprovides a simple, low cost, practical, heavy duty centrifugal pump withimproved non-clogging properties, and ease of maintenance, well adaptedfor continuous use with contaminated liquids. Although a power washinginstallation has been described, it is to. be understood that aspects ofthe invention make it well suited for adaptation to a wide variety ofsevere operating conditions. For example, the invention has beenY usedin other installations, such as in curtain spray systems, which requirea high capacity pump which will handle solids such as lumps of dirt.rIlhe dimensions given above are merely illustrative,l heing those usedin a successful pumping assembly embodying my invention.

l claim:

1. A centrifugal pump for handling contaminated liquids withoutclogging, comprising an impeller including` an imperforate member havingblades projecting from its front face, said blades being in an annulararea with their inner edges spaced out from the axis of rotationdeiining a central impeller space having a diameter larger than one-halfof the diameter of the circle defined by their outer edges, the heightof said blades at their inner edges being greater than at their outeredges, said blades being inclined backwardly from their inner t outeredges with respect to the direction of rotation, aY casing surroundingsaid impeller and having a iirst wall with a relatively large axialintake port, said wall providing4 a conical annular face injuxtaposition to Said blades, the outstanding edges of said blades beingcurved, so as to provide a uniform clearance with said conical annularsurface, a generally spiral-shaped scroll forming the periphery of saidcasing, a second wall for said casing in spaced relationship with saidrst wall and having an axial shaft opening therein, outer portions ofsaid walls and said scroll dening a curved peripheral discharge channelof gradually expanding cross section within, said scroll, a shaft endextending into said casing through said opening and having a clearancespace therearound, said impeller being secured to said shaft end withlsaid member spaced from said second wall, theinner edges of said bladessubstantially in alignment with the edge of said intake port, and aplurality of auxiliary impeller blade portions projecting from the rearface of said member toward said second wall to permit controlled flow ofliquid back from said discharge channel past said disk and through saidshaft opening, the auxiliary blades having a uniform clearance from thecover plate equal to the clearance ofthe other blades from said conicalannular surface.

2. A centrifugal pump for handling contaminated liquids without cloggingcomprising mounting means, an upper support extending up from saidmounting, upper and lower vertically alignedbearings, said upper bearingibeing secured to saidsupport above said mounting means, said lowerbearing being above said mounting, a vertical rotatable shaft carried bysaid bearings, driving means connected to the upper end of said shaft,the lower end of said shaft projecting down a substantial distance belowsaid lower bearing and below said mounting means, a lower supportextending down from said mounting means, a horizontal cover platesecured to the lower end of said lower support, said horizontal coverplate having a central opening down through which, projects the lowerend of said shaft and providing a clearance spacing around the portionof the shaft passing therethrough, said lower support providing accessto the outside of the pump from the clearance spacing in said` opening,said cover plate. defining the top surface of an impeller chamber, ahorizontal circular impeller disc secured to the lower end of said shaftbeneath said cover plate and providing a substantial clearance abovesaid disc, said impeller disc having a plurality of impeller bladesprojecting down from its lower face and arranged in an annular patternwith their outer edges adjacent to the edge of the peller disc and withtheir inner edges each being spaced out f romthe center, of the impellerdisc by equal sub1 stantial distances defining a lar'ge central impellerspace inside of said inner edges, said blades incliningbackwardly fromtheir inner edges with respect to the direction of'rotation of theimpeller disc, and the spaces between the outer edges `of said bladesbeing unobstructed, the lower edges of said blades tapering upwardlyfrom their inner edges to their outer edges, a casing ring defining thebottom` of said impeller chamber and having a downwardly projectinginner lip defining a large open intake port which is directly beneathsaid central impeller space and is adjacent to the inner edges of saidblades, said casing ring having a truncated conical inner surfacesloping upwardly and outwardly from the intake port and uniformlyclosely spaced to the lower edges of said blades, whereby anycontaminating agents in said fluid entering said intake port aredirectly exposed to the chewing action of said blades, a pump scrollsecured to said casing ring and detachably secured to said cover plateand dening a discharge channel surrounding the unobstructed outer edgesof said blades, and auxiliary blades on the upper surface of saidirnpeller disc adjacent to the cover plate for limiting the reverse iiowof liquid from said discharge channel past the upper surface of saidimpeller disc and up through the clearance spacing around the portion ofthe. shaft which passes through said cover.

3. A centrifugal pump for handling contaminated liquids without cloggingcomprising mounting means, upper and lower vertically aligned bearingssupported by said mounting means, a vertical rotatable shaft carried bysaid bearings, driving means connected to the upper end of said shaft,the lower end of said shaft projecting down a substantial distance belowsaid lower bearing, a lower support extending down from said mountingmeans, a horizontal cover plate secured to the lower end of said lowersupport, said horizontal cover plate having a central opening downthrough which projects the lower end of said shaft with a spacin-gtherearound, said cover plate defining the top surface of an impellerchamber, an outwardly extending impeller disc secured to the lower endof said shaft beneath said cover plate with a substantial clearancebetween said impeller disc and cover plate, said lower support providingan opening to the outside of the pump from said spacing around theshaft, said impeller disc having a plurality of impeller Ibladesprojecting down from its lower face and arranged in an annular pattern-with their outer edges adjacent to the edge of the impeller disc. andwith their inner edges heing spaced out a substantial distance from thecenter of said impeller disc so as to define a central impeller spaceamong the inner edges of the blades, the diameter of said centralimpeller space being more than one-half of the diameter of said impellerdisc, said blades being inclined backwardly at an angle with respect tothe direction of rotation, the lower edges of said blades incliningupwardly from their inner edges to their outer edges, a casing ringyforming the bottom, of said impeller chamber and having a downwardlyprojecting inner lip defining a large open intake port which is adjacentto the inner edges of said blades and has a diameter more than onehalfof the diameter of said impeller disc, said casing ring having atruncated conical inner surface which is uniformly spaced from the loweredges of said blades, a pump scroll secured to said casing ring andremov- .ably secured to said cover plate and defining a dischargechannel surrounding the outer edges of said blades, and auxiliary bladeson the upper surface of said impeller disc adjacent to the cover platefor limiting the reverse flow of liquid from said discharge channel pastthe upliquids without clogging comprising mounting means,

upper and lower vertically aligned bearings supported by said mountingmeans, a vertical rotatable shaft carried by said bearings, drivingmeans on the upper end of said shaft, the lower end of said shaftprojecting down a substantial distance below said lower bearing, a lowersupport extending down from said mounting means, a cover plate extendingoutwardly from the lower end of said lower support, said cover platehaving a central opening down through which extends the lower end ofsaid shaft having a spacing therearound, said cover plate defining thetop surface of an impeller chamber, an outwardly extending impeller discsecured to the lower end of said shaft beneath said cover plate with asubstantial clearance between the top of said impeller disc and thecover plate, said lower support providing communication to the outsideof the pump from said spacing around the shaft, said impeller dischaving a plurality of planar impeller blades projecting down from itslower face and arranged in an annular pattern with their outer edgesadjacent to the edge of the impeller disc and with their inner edges:being spaced out a substantial distance from the center of saidimpeller disc so as to define a central impeller space among the inneredges of the blades, the diameter of said central impeller space beingmore than one-half of the diameter of said impeller disc, said bladesbeing inclined backwardly at an angle of 70 with respect to radii fromthe axis of rotation passing through their inner edges, the lower edgesof said blades inclining upwardly from their inner edges to their outeredges, a casing ring forming the bottom of said impeller chamber andhaving a downwardly projecting inner lip defining a large open intakeport which is adjacent to the inner edges of said blades and Ihas adiameter more than one-half of the diameter of said impeller disc, saidcasing ring having a truncated conical inner surface which is uniformlyspaced from the lower edges of said blades, a pump scroll secured tosaid casing ring and removably secured to said cover plate and defininga discharge channel surrounding the outer edges of said blades, andauxiliary blades on the upper surface of said impeller disc adjacent tothe cover plate for limiting the reverse ow of liquid from saiddischarge channel past the upper surface of said irnpeller disc and outthrough said spacing around the shaft.

5. A non-clogging centrifugal pump for handling contaminated liquidscomprising a rotatable shaft, an impeller connected to the end of theshaft and having a disc-like member with the shaft extending out fromthe rear surface of the member and a plurality of blades projecting fromits front face, said blades being in an annular pattern around the axisof the shaft, the inner edges of said blades being spaced a substantialdistance from the axis defining a central impellerspace, the outer edgesof said blades being adjacent to the periphery of said member, saidblades decreasing in height from their inner to their outer edges andinclining backwardly from the central impeller space with respect to thedirection of rotation, a support around said shaft, a pump casingcarried by said support, said casing comprising a cover plate secured tothe lower end of said support and having a central opening through whichthe shaft extends with a substantial clearance there-V around, agenerally spiral pump scroll removably secured to the edge of said coverplate and defining a curved peripheral discharge channel of expandingcross section surrounding the outer edges of said blades, a truncatedconical casing portion secured to said pump scroll and having an insidesurface adjacent to said blades, said truncated conical casing portionhaving a downwardly projecting central lip defining a large unobstructedintake port adjacent to the central impeller space, the inner surface ofthe truncated conical portion adjacent to the blades sloping upwardlyaway from the intake port at an angle of 25 with respect to thehorizontal.

6. A non-clogging centrifugal pump for handling contaminated liquidscomprising mounting means for said pump, upper and lower verticallyaligned bearings for said pump, a vertical rotatable shaft carried bysaid bearings, driving means near the upper end of said shaft, the lowerend of said shaft projecting down a substantial distance below saidlower bearing, a lower support connected to said mounting means andextending down therefrom, an outwardly extending cover plate secured tothe lower end of said lower support, said cover plate having a centralopening down through which projects the lower end of said shaft with asignificant clearance around said shaft, said lower support permittingliquid passing through the clearance to pass out of the pump, said coverplate defining the top surface of an impeller chamber, a disclikeimpeller member secured to the lower end of said shaft beneath saidcover plate, said impeller member having a plurality of impeller bladesprojecting down t from its lower face, said impeller blades beingarranged Ain an annular pattern with their outer edges adjacent to theouter limits of the impeller member and with their inner edges beingspaced out a substantial distance from the axis of the shaft defining acentral impeller space, said blades being inclined backwardly withrespect to the direction of rotation, the lower edges of said blades inclining upwardly from their inner edges to their outer edges, a casingring defining the bottom of said impeller chamber and having adownwardly projecting inner lip defining a large intake port which isadjacent to the inner edges of said blades, said casing ring having atruncated conical inner surface which is uniformly spaced s of an inchfrom the lower edges of said blades, a pump scroll secured to saidcasing ring and detachably connected to said cover plate and defining adischarge channel surrounding the outer edges of said blades, andauxiliary blades on the upper surface of said impeller disc adjacent tothe cover plate for restricting the reverse iiow from said dischargechamber through said clearance space around the portion of the shaftpassing through the cover plate, the upper edges of said auxiliaryblades being uniformly spaced Ms of an inch from the cover plate.

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